1. Field of the Invention
The present invention relates to a shell-type centrifuge rotor.
2. Description of the Prior Art
So-called shell-type rotors are well known in the centrifuge art. In the typical instance a shell-type rotor includes a generally planar body member onto which is attached an upper plate. The upper plate has an array of openings sized to accept sample containers. When received in the openings in the plate the containers project into an open space defined between the upper surface of the body member and the undersurface of the plate.
U.S. Pat. No. 4,449,965 (Strain) is believed a representative example of such a rotor construction. Typically, no seal is provided between the body and the plate. In the rotor disclosed in U.S. Pat. No. 4,832,679 (Bader) the radially outer peripheral region of the body curves inwardly toward the axis of rotation to define a trough. The trough serves to trap liquid which may escape from the containers into the open space.
Owing to its relatively low cost of manufacture a shell-type rotor is a popular rotor choice when a clinician is presented with the task of spinning a relatively small sized sample (on the order of two milliliters). Moreover, a shell-type rotor may be used for protocols that extend into the superspeed regime, with rotational speeds on the order of fifteen thousand rpm being typical.
As with any rotor, there is a possibility that a shell-type rotor may fail in operation. Typical causes of failure include fracture due to fatigue or due to excessive forces generated by an overspeed condition. Even though relatively light in weight, because of the rotational speed at which it may be operated, failure of a shell-type rotor may cause significant damage to the centrifuge instrument in which it is used.
It is, therefore, believed advantageous to provide a braking system for a shell-type rotor that minimizes the risk of damage to the instrument in the event of rotor failure. In addition, it is believed advantageous to provide a seal arrangement for sealing the space between the body and upper plate of a shell-type rotor.